| Message ID | 1379698757-25232-1-git-send-email-soren.brinkmann@xilinx.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 20, 2013 at 10:39:17AM -0700, Soren Brinkmann wrote: > Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. > The devices generate low-jitter clock signals and are reprogrammable via > an I2C interface. > > Cc: Guenter Roeck <linux@roeck-us.net> > Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> > --- > v4: > - actually check and handle error on clk_set_rate() call > > v3: > - add delay in the path for small frequency changes, which can take up > to 100us according to the data sheet > - use real range for usleep_range() argument > - use dev_err() over dev_warn() in set_rate() > - add list of applicable devices for 7ppm DT prop > - remove comments regarding platform data > - ignore 7ppm DT prop for incompatible devices > - replace raw numbers with #defines > - convert DT prop 'temperature-stability' from boolean to u32 > - make 'temperature-stability' DT prop required (actually not fully > true, for 59x it is ignored and the driver does not require its > presence) > > v2: > - document clock-output-names in bindings documentation > - don't use wildcards in compatibility string > - change Kconfig entry to "... 570 and compatible devices" > - change some indentation flaws > - use 10000 as MIN and MAX value in usleep_range > - fail probe() if 'factory-fout' is not provided in DT > - default factory fout #defines removed > - use i2c driver_data instead of OF data > - remove some related structs and data > - rename DT property 'initial-fout' => 'clock-frequency' (like si5351 > driver) > - add some more details regarding the 'factory-fout' DT property > --- > .../devicetree/bindings/clock/silabs,si570.txt | 39 ++ > drivers/clk/Kconfig | 10 + > drivers/clk/Makefile | 1 + > drivers/clk/clk-si570.c | 536 +++++++++++++++++++++ > 4 files changed, 586 insertions(+) > create mode 100644 Documentation/devicetree/bindings/clock/silabs,si570.txt > create mode 100644 drivers/clk/clk-si570.c > > diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt > new file mode 100644 > index 0000000..26aab5c > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/silabs,si570.txt > @@ -0,0 +1,39 @@ > +Binding for Silicon Labs 570, 571, 598 and 599 programmable > +I2C clock generators. > + > +Reference > +This binding uses the common clock binding[1]. Details about the devices can be > +found in the data sheets[2][3]. > + > +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt > +[2] Si570/571 Data Sheet > + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf > +[3] Si598/599 Data Sheet > + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf > + > +Required properties: > + - compatible: Shall be one of "silabs,si570", "silabs,si571", > + "silabs,si598", "silabs,si599" > + - reg: I2C device address. > + - #clock-cells: From common clock bindings: Shall be 0. > + - factory-fout: Factory set default frequency. This frequency is part specific. > + The correct frequency for the part used has to be provided in > + order to generate the correct output frequencies. For more > + details, please refer to the data sheet. > + - temperature-stability: Temperature stability of the device. Should be one of: > + 7, 20, 50 or 100. > + It might make sense to specify that this is in microseconds. > +Optional properties: > + - clock-output-names: From common clock bindings. Recommended to be "si570". > + - clock-frequency: Output frequency to generate. This defines the output > + frequency set during boot. It can be reprogrammed during > + runtime through the common clock framework. > + > +Example: > + si570: clock-generator@5d { > + #clock-cells = <0>; > + compatible = "silabs,si570"; > + temperatur-stability = <50>; temperature > + reg = <0x5d>; > + factory-fout = <156250000>; > + }; > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig > index 279407a..349b88a 100644 > --- a/drivers/clk/Kconfig > +++ b/drivers/clk/Kconfig > @@ -64,6 +64,16 @@ config COMMON_CLK_SI5351 > This driver supports Silicon Labs 5351A/B/C programmable clock > generators. > > +config COMMON_CLK_SI570 > + tristate "Clock driver for SiLabs 570 and compatible devices" > + depends on I2C > + depends on OF > + select REGMAP_I2C > + help > + ---help--- > + This driver supports Silicon Labs 570/571/598/599 programmable > + clock generators. > + > config COMMON_CLK_S2MPS11 > tristate "Clock driver for S2MPS11 MFD" > depends on MFD_SEC_CORE > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile > index 7b11106..c0e94b3 100644 > --- a/drivers/clk/Makefile > +++ b/drivers/clk/Makefile > @@ -40,6 +40,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o > obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o > obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o > obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o > +obj-$(CONFIG_COMMON_CLK_SI570) += clk-si570.o > obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o > obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o > obj-$(CONFIG_CLK_PPC_CORENET) += clk-ppc-corenet.o > diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c > new file mode 100644 > index 0000000..13c2091 > --- /dev/null > +++ b/drivers/clk/clk-si570.c > @@ -0,0 +1,536 @@ > +/* > + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO > + * > + * Copyright (C) 2010, 2011 Ericsson AB. > + * Copyright (C) 2011 Guenter Roeck. > + * Copyright (C) 2011 - 2013 Xilinx Inc. > + * > + * Author: Guenter Roeck <guenter.roeck@ericsson.com> > + * Sören Brinkmann <soren.brinkmann@xilinx.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/clk-provider.h> > +#include <linux/delay.h> > +#include <linux/module.h> > +#include <linux/i2c.h> > +#include <linux/regmap.h> > +#include <linux/slab.h> > + > +/* Si570 registers */ > +#define SI570_REG_HS_N1 7 > +#define SI570_REG_N1_RFREQ0 8 > +#define SI570_REG_RFREQ1 9 > +#define SI570_REG_RFREQ2 10 > +#define SI570_REG_RFREQ3 11 > +#define SI570_REG_RFREQ4 12 > +#define SI570_REG_CONTROL 135 > +#define SI570_REG_FREEZE_DCO 137 > +#define SI570_DIV_OFFSET_7PPM 6 > + > +#define HS_DIV_SHIFT 5 > +#define HS_DIV_MASK 0xe0 > +#define HS_DIV_OFFSET 4 > +#define N1_6_2_MASK 0x1f > +#define N1_1_0_MASK 0xc0 > +#define RFREQ_37_32_MASK 0x3f > + > +#define SI570_MIN_FREQ 10000000L > +#define SI570_MAX_FREQ 1417500000L > +#define SI598_MAX_FREQ 525000000L > + > +#define FDCO_MIN 4850000000LL > +#define FDCO_MAX 5670000000LL > + > +#define SI570_CNTRL_RECALL (1 << 0) > +#define SI570_CNTRL_FREEZE_M (1 << 5) > +#define SI570_CNTRL_NEWFREQ (1 << 6) > + > +#define SI570_FREEZE_DCO (1 << 4) > + > +/** > + * struct clk_si570: > + * @hw: Clock hw struct > + * @regmap: Device's regmap > + * @div_offset: Rgister offset for dividers > + * @max_freq: Maximum frequency for this device > + * @fxtal: Factory xtal frequency > + * @n1: Clock divider N1 > + * @hs_div: Clock divider HSDIV > + * @rfreq: Clock multiplier RFREQ > + * @frequency: Current output frequency > + * @i2c_client: I2C client pointer > + */ > +struct clk_si570 { > + struct clk_hw hw; > + struct regmap *regmap; > + unsigned int div_offset; > + u64 max_freq; > + u64 fxtal; > + unsigned int n1; > + unsigned int hs_div; > + u64 rfreq; > + u64 frequency; > + struct i2c_client *i2c_client; > +}; > +#define to_clk_si570(_hw) container_of(_hw, struct clk_si570, hw) > + > +enum clk_si570_variant { > + si57x, > + si59x > +}; > + > +/** > + * si570_get_divs() - Read clock dividers from HW > + * @data: Pointer to struct clk_si570 > + * @rfreq: Fractional multiplier (output) > + * @n1: Divider N1 (output) > + * @hs_div: Divider HSDIV (output) > + * Returns 0 on success, negative errno otherwise. > + * > + * Retrieve clock dividers and multipliers from the HW. > + */ > +static int si570_get_divs(struct clk_si570 *data, u64 *rfreq, > + unsigned int *n1, unsigned int *hs_div) > +{ > + int err; > + u8 reg[6]; > + u64 tmp; > + > + err = regmap_bulk_read(data->regmap, SI570_REG_HS_N1 + data->div_offset, > + reg, ARRAY_SIZE(reg)); > + if (err) > + return err; > + > + *hs_div = ((reg[0] & HS_DIV_MASK) >> HS_DIV_SHIFT) + HS_DIV_OFFSET; > + *n1 = ((reg[0] & N1_6_2_MASK) << 2) + ((reg[1] & N1_1_0_MASK) >> 6) + 1; > + /* Handle invalid cases */ > + if (*n1 > 1) > + *n1 &= ~1; > + > + tmp = reg[1] & RFREQ_37_32_MASK; > + tmp = (tmp << 8) + reg[2]; > + tmp = (tmp << 8) + reg[3]; > + tmp = (tmp << 8) + reg[4]; > + tmp = (tmp << 8) + reg[5]; > + *rfreq = tmp; > + > + return 0; > +} > + > +/** > + * si570_get_defaults() - Get default values > + * @data: Driver data structure > + * @fout: Factory frequency output > + * Returns 0 on success, negative errno otherwise. > + */ > +static int si570_get_defaults(struct clk_si570 *data, u64 fout) > +{ > + int err; > + u64 fdco; > + > + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_RECALL); > + > + err = si570_get_divs(data, &data->rfreq, &data->n1, &data->hs_div); > + if (err) > + return err; > + > + /* > + * Accept optional precision loss to avoid arithmetic overflows. > + * Acceptable per Silicon Labs Application Note AN334. > + */ > + fdco = fout * data->n1 * data->hs_div; > + if (fdco >= (1LL << 36)) > + data->fxtal = div64_u64(fdco << 24, data->rfreq >> 4); > + else > + data->fxtal = div64_u64(fdco << 28, data->rfreq); > + > + data->frequency = fout; > + > + return 0; > +} > + > +/** > + * si570_update_rfreq() - Update clock multiplier > + * @data: Driver data structure > + * Passes on regmap_bulk_write() return value. > + */ > +static int si570_update_rfreq(struct clk_si570 *data) > +{ > + u8 reg[5]; > + > + reg[0] = ((data->n1 - 1) << 6) | > + ((data->rfreq >> 32) & RFREQ_37_32_MASK); > + reg[1] = (data->rfreq >> 24) & 0xff; > + reg[2] = (data->rfreq >> 16) & 0xff; > + reg[3] = (data->rfreq >> 8) & 0xff; > + reg[4] = data->rfreq & 0xff; > + > + return regmap_bulk_write(data->regmap, SI570_REG_N1_RFREQ0 + > + data->div_offset, reg, ARRAY_SIZE(reg)); > +} > + > +/** > + * si570_calc_divs() - Caluclate clock dividers > + * @frequency: Target frequency > + * @data: Driver data structure > + * @out_rfreq: RFREG fractional multiplier (output) > + * @out_n1: Clock divider N1 (output) > + * @out_hs_div: Clock divider HSDIV (output) > + * Returns 0 on success, negative errno otherwise. > + * > + * Calculate the clock dividers (@out_hs_div, @out_n1) and clock multiplier > + * (@out_rfreq) for a given target @frequency. > + */ > +static int si570_calc_divs(unsigned long frequency, struct clk_si570 *data, > + u64 *out_rfreq, unsigned int *out_n1, unsigned int *out_hs_div) > +{ > + int i; > + unsigned int n1, hs_div; > + u64 fdco, best_fdco = ULLONG_MAX; > + static const uint8_t si570_hs_div_values[] = { 11, 9, 7, 6, 5, 4 }; > + > + for (i = 0; i < ARRAY_SIZE(si570_hs_div_values); i++) { > + hs_div = si570_hs_div_values[i]; > + /* Calculate lowest possible value for n1 */ > + n1 = div_u64(div_u64(FDCO_MIN, hs_div), frequency); > + if (!n1 || (n1 & 1)) > + n1++; > + while (n1 <= 128) { > + fdco = (u64)frequency * (u64)hs_div * (u64)n1; > + if (fdco > FDCO_MAX) > + break; > + if (fdco >= FDCO_MIN && fdco < best_fdco) { > + *out_n1 = n1; > + *out_hs_div = hs_div; > + *out_rfreq = div64_u64(fdco << 28, data->fxtal); > + best_fdco = fdco; > + } > + n1 += (n1 == 1 ? 1 : 2); > + } > + } > + > + if (best_fdco == ULLONG_MAX) > + return -EINVAL; > + > + return 0; > +} > + > +static unsigned long si570_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ > + int err; > + u64 rfreq, rate; > + unsigned int n1, hs_div; > + struct clk_si570 *data = to_clk_si570(hw); > + > + err = si570_get_divs(data, &rfreq, &n1, &hs_div); > + if (err) { > + dev_err(&data->i2c_client->dev, "unable to recalc rate\n"); > + return data->frequency; > + } > + > + rfreq = div_u64(rfreq, hs_div * n1); > + rate = (data->fxtal * rfreq) >> 28; > + > + return rate; > +} > + > +static long si570_round_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long *parent_rate) > +{ > + int err; > + u64 rfreq; > + unsigned int n1, hs_div; > + struct clk_si570 *data = to_clk_si570(hw); > + > + if (!rate) > + return 0; > + > + if (div64_u64(abs(rate - data->frequency) * 10000LL, > + data->frequency) < 35) { > + rfreq = div64_u64((data->rfreq * rate) + > + div64_u64(data->frequency, 2), data->frequency); > + n1 = data->n1; > + hs_div = data->hs_div; > + > + } else { > + err = si570_calc_divs(rate, data, &rfreq, &n1, &hs_div); > + if (err) { > + dev_err(&data->i2c_client->dev, > + "unable to round rate\n"); > + return 0; > + } > + } > + > + return rate; > +} > + > +/** > + * si570_set_frequency() - Adjust output frequency > + * @data: Driver data structure > + * @frequency: Target frequency > + * Returns 0 on success. > + * > + * Update output frequency for big frequency changes (> 3,500 ppm). > + */ > +static int si570_set_frequency(struct clk_si570 *data, unsigned long frequency) > +{ > + int err; > + > + err = si570_calc_divs(frequency, data, &data->rfreq, &data->n1, > + &data->hs_div); > + if (err) > + return err; > + > + /* > + * The DCO reg should be accessed with a read-modify-write operation > + * per AN334 > + */ > + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, SI570_FREEZE_DCO); > + regmap_write(data->regmap, SI570_REG_HS_N1 + data->div_offset, > + ((data->hs_div - HS_DIV_OFFSET) << HS_DIV_SHIFT) | > + (((data->n1 - 1) >> 2) & N1_6_2_MASK)); > + si570_update_rfreq(data); > + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, 0); > + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_NEWFREQ); > + > + /* Applying a new frequency can take up to 10ms */ > + usleep_range(10000, 12000); > + > + return 0; > +} > + > +/** > + * si570_set_frequency_small() - Adjust output frequency > + * @data: Driver data structure > + * @frequency: Target frequency > + * Returns 0 on success. > + * > + * Update output frequency for small frequency changes (< 3,500 ppm). > + */ > +static int si570_set_frequency_small(struct clk_si570 *data, > + unsigned long frequency) > +{ > + /* > + * This is a re-implementation of DIV_ROUND_CLOSEST > + * using the div64_u64 function lieu of letting the compiler > + * insert EABI calls > + */ > + data->rfreq = div64_u64((data->rfreq * frequency) + > + div_u64(data->frequency, 2), data->frequency); > + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_FREEZE_M); > + si570_update_rfreq(data); > + regmap_write(data->regmap, SI570_REG_CONTROL, 0); > + > + /* Applying a new frequency (small change) can take up to 100us */ > + usleep_range(100, 200); > + > + return 0; > +} > + > +static int si570_set_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long parent_rate) > +{ > + struct clk_si570 *data = to_clk_si570(hw); > + struct i2c_client *client = data->i2c_client; > + int err; > + > + if (rate < SI570_MIN_FREQ || rate > data->max_freq) { > + dev_err(&client->dev, > + "requested frequency %lu Hz is out of range\n", rate); > + return -EINVAL; > + } > + > + if (div64_u64(abs(rate - data->frequency) * 10000LL, > + data->frequency) < 35) > + err = si570_set_frequency_small(data, rate); > + else > + err = si570_set_frequency(data, rate); > + > + if (err) > + return err; > + > + data->frequency = rate; > + > + return 0; > +} > + > +static const struct clk_ops si570_clk_ops = { > + .recalc_rate = si570_recalc_rate, > + .round_rate = si570_round_rate, > + .set_rate = si570_set_rate, > +}; > + > +static bool si570_regmap_is_volatile(struct device *dev, unsigned int reg) > +{ > + switch (reg) { > + case SI570_REG_CONTROL: > + return true; > + default: > + return false; > + } > +} > + > +static bool si570_regmap_is_writeable(struct device *dev, unsigned int reg) > +{ > + switch (reg) { > + case SI570_REG_HS_N1 ... (SI570_REG_RFREQ4 + SI570_DIV_OFFSET_7PPM): > + case SI570_REG_CONTROL: > + case SI570_REG_FREEZE_DCO: > + return true; > + default: > + return false; > + } > +} > + > +static struct regmap_config si570_regmap_config = { > + .reg_bits = 8, > + .val_bits = 8, > + .cache_type = REGCACHE_RBTREE, > + .max_register = 137, > + .writeable_reg = si570_regmap_is_writeable, > + .volatile_reg = si570_regmap_is_volatile, > +}; > + > +static int si570_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct clk_si570 *data; > + struct clk_init_data init; > + struct clk *clk; > + u32 initial_fout, factory_fout, stability; > + int err; > + enum clk_si570_variant variant = id->driver_data; > + > + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + init.ops = &si570_clk_ops; > + init.flags = CLK_IS_ROOT; > + init.num_parents = 0; > + data->hw.init = &init; > + data->i2c_client = client; > + > + if (variant == si57x) { > + err = of_property_read_u32(client->dev.of_node, > + "temperature-stability", &stability); > + if (err) { > + dev_err(&client->dev, > + "'temperature-stability' property missing\n"); > + return err; > + } > + /* adjust register offsets for 7ppm devices */ > + if (stability == 7) > + data->div_offset = SI570_DIV_OFFSET_7PPM; > + > + data->max_freq = SI570_MAX_FREQ; > + } else { > + data->max_freq = SI598_MAX_FREQ; > + } > + > + if (of_property_read_string(client->dev.of_node, "clock-output-names", > + &init.name)) > + init.name = client->dev.of_node->name; > + > + err = of_property_read_u32(client->dev.of_node, "factory-fout", > + &factory_fout); > + if (err) { > + dev_err(&client->dev, "'factory-fout' property missing\n"); > + return err; > + } > + > + data->regmap = devm_regmap_init_i2c(client, &si570_regmap_config); > + if (IS_ERR(data->regmap)) { > + dev_err(&client->dev, "failed to allocate register map\n"); > + return PTR_ERR(data->regmap); > + } > + > + i2c_set_clientdata(client, data); > + err = si570_get_defaults(data, factory_fout); > + if (err) > + return err; > + > + clk = devm_clk_register(&client->dev, &data->hw); > + if (IS_ERR(clk)) { > + dev_err(&client->dev, "clock registration failed\n"); > + return PTR_ERR(clk); > + } > + err = of_clk_add_provider(client->dev.of_node, of_clk_src_simple_get, > + clk); > + if (err) { > + dev_err(&client->dev, "unable to add clk provider\n"); > + return err; > + } > + > + /* Read the requested initial output frequency from device tree */ > + if (!of_property_read_u32(client->dev.of_node, "clock-frequency", > + &initial_fout)) { > + err = clk_set_rate(clk, initial_fout); > + if (err) { > + of_clk_del_provider(client->dev.of_node); > + clk_unregister(data->hw.clk); Is that needed ? I would have thought it isn't because you use a devm_ function to register it. Not that I understand the clk code, but getting clk from the registration function and unregistering hw.clk (without seting it) sems a bit odd. Is it well defined that you have to unregister hw.clk ? > + return err; > + } > + } > + > + /* Display a message indicating that we've successfully registered */ > + dev_info(&client->dev, "registered, current frequency %llu Hz\n", > + data->frequency); > + > + return 0; > +} > + > +static int si570_remove(struct i2c_client *client) > +{ > + struct clk_si570 *data = i2c_get_clientdata(client); > + > + of_clk_del_provider(client->dev.of_node); > + clk_unregister(data->hw.clk); > + > + return 0; > +} > + > +static const struct i2c_device_id si570_id[] = { > + { "si570", si57x }, > + { "si571", si57x }, > + { "si598", si59x }, > + { "si599", si59x }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, si570_id); > + > +static const struct of_device_id clk_si570_of_match[] = { > + { .compatible = "silabs,si570" }, > + { .compatible = "silabs,si571" }, > + { .compatible = "silabs,si598" }, > + { .compatible = "silabs,si599" }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, clk_si570_of_match); > + > +static struct i2c_driver si570_driver = { > + .driver = { > + .name = "si570", > + .of_match_table = of_match_ptr(clk_si570_of_match), > + }, > + .probe = si570_probe, > + .remove = si570_remove, > + .id_table = si570_id, > +}; > +module_i2c_driver(si570_driver); > + > +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>"); > +MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xilinx.com"); > +MODULE_DESCRIPTION("Si570 driver"); > +MODULE_LICENSE("GPL"); > -- > 1.8.4 > >
On Fri, Sep 20, 2013 at 11:15:29AM -0700, Guenter Roeck wrote: > On Fri, Sep 20, 2013 at 10:39:17AM -0700, Soren Brinkmann wrote: > > Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. > > The devices generate low-jitter clock signals and are reprogrammable via > > an I2C interface. > > > > Cc: Guenter Roeck <linux@roeck-us.net> > > Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> > > --- > > v4: > > - actually check and handle error on clk_set_rate() call > > > > v3: > > - add delay in the path for small frequency changes, which can take up > > to 100us according to the data sheet > > - use real range for usleep_range() argument > > - use dev_err() over dev_warn() in set_rate() > > - add list of applicable devices for 7ppm DT prop > > - remove comments regarding platform data > > - ignore 7ppm DT prop for incompatible devices > > - replace raw numbers with #defines > > - convert DT prop 'temperature-stability' from boolean to u32 > > - make 'temperature-stability' DT prop required (actually not fully > > true, for 59x it is ignored and the driver does not require its > > presence) > > > > v2: > > - document clock-output-names in bindings documentation > > - don't use wildcards in compatibility string > > - change Kconfig entry to "... 570 and compatible devices" > > - change some indentation flaws > > - use 10000 as MIN and MAX value in usleep_range > > - fail probe() if 'factory-fout' is not provided in DT > > - default factory fout #defines removed > > - use i2c driver_data instead of OF data > > - remove some related structs and data > > - rename DT property 'initial-fout' => 'clock-frequency' (like si5351 > > driver) > > - add some more details regarding the 'factory-fout' DT property > > --- > > .../devicetree/bindings/clock/silabs,si570.txt | 39 ++ > > drivers/clk/Kconfig | 10 + > > drivers/clk/Makefile | 1 + > > drivers/clk/clk-si570.c | 536 +++++++++++++++++++++ > > 4 files changed, 586 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/clock/silabs,si570.txt > > create mode 100644 drivers/clk/clk-si570.c > > > > diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt > > new file mode 100644 > > index 0000000..26aab5c > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/clock/silabs,si570.txt > > @@ -0,0 +1,39 @@ > > +Binding for Silicon Labs 570, 571, 598 and 599 programmable > > +I2C clock generators. > > + > > +Reference > > +This binding uses the common clock binding[1]. Details about the devices can be > > +found in the data sheets[2][3]. > > + > > +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt > > +[2] Si570/571 Data Sheet > > + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf > > +[3] Si598/599 Data Sheet > > + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf > > + > > +Required properties: > > + - compatible: Shall be one of "silabs,si570", "silabs,si571", > > + "silabs,si598", "silabs,si599" > > + - reg: I2C device address. > > + - #clock-cells: From common clock bindings: Shall be 0. > > + - factory-fout: Factory set default frequency. This frequency is part specific. > > + The correct frequency for the part used has to be provided in > > + order to generate the correct output frequencies. For more > > + details, please refer to the data sheet. > > + - temperature-stability: Temperature stability of the device. Should be one of: > > + 7, 20, 50 or 100. > > + > It might make sense to specify that this is in microseconds. ppm, but yes giving the unit is a good idea. > > > +Optional properties: > > + - clock-output-names: From common clock bindings. Recommended to be "si570". > > + - clock-frequency: Output frequency to generate. This defines the output > > + frequency set during boot. It can be reprogrammed during > > + runtime through the common clock framework. > > + > > +Example: > > + si570: clock-generator@5d { > > + #clock-cells = <0>; > > + compatible = "silabs,si570"; > > + temperatur-stability = <50>; > > temperature damn typos. > > > + reg = <0x5d>; > > + factory-fout = <156250000>; > > + }; [...] > > diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c > > new file mode 100644 > > index 0000000..13c2091 > > --- /dev/null > > +++ b/drivers/clk/clk-si570.c [...] > > +static int si570_probe(struct i2c_client *client, > > + const struct i2c_device_id *id) > > +{ > > + struct clk_si570 *data; > > + struct clk_init_data init; > > + struct clk *clk; > > + u32 initial_fout, factory_fout, stability; > > + int err; > > + enum clk_si570_variant variant = id->driver_data; > > + > > + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); > > + if (!data) > > + return -ENOMEM; > > + > > + init.ops = &si570_clk_ops; > > + init.flags = CLK_IS_ROOT; > > + init.num_parents = 0; > > + data->hw.init = &init; > > + data->i2c_client = client; > > + > > + if (variant == si57x) { > > + err = of_property_read_u32(client->dev.of_node, > > + "temperature-stability", &stability); > > + if (err) { > > + dev_err(&client->dev, > > + "'temperature-stability' property missing\n"); > > + return err; > > + } > > + /* adjust register offsets for 7ppm devices */ > > + if (stability == 7) > > + data->div_offset = SI570_DIV_OFFSET_7PPM; > > + > > + data->max_freq = SI570_MAX_FREQ; > > + } else { > > + data->max_freq = SI598_MAX_FREQ; > > + } > > + > > + if (of_property_read_string(client->dev.of_node, "clock-output-names", > > + &init.name)) > > + init.name = client->dev.of_node->name; > > + > > + err = of_property_read_u32(client->dev.of_node, "factory-fout", > > + &factory_fout); > > + if (err) { > > + dev_err(&client->dev, "'factory-fout' property missing\n"); > > + return err; > > + } > > + > > + data->regmap = devm_regmap_init_i2c(client, &si570_regmap_config); > > + if (IS_ERR(data->regmap)) { > > + dev_err(&client->dev, "failed to allocate register map\n"); > > + return PTR_ERR(data->regmap); > > + } > > + > > + i2c_set_clientdata(client, data); > > + err = si570_get_defaults(data, factory_fout); > > + if (err) > > + return err; > > + > > + clk = devm_clk_register(&client->dev, &data->hw); > > + if (IS_ERR(clk)) { > > + dev_err(&client->dev, "clock registration failed\n"); > > + return PTR_ERR(clk); > > + } > > + err = of_clk_add_provider(client->dev.of_node, of_clk_src_simple_get, > > + clk); > > + if (err) { > > + dev_err(&client->dev, "unable to add clk provider\n"); > > + return err; > > + } > > + > > + /* Read the requested initial output frequency from device tree */ > > + if (!of_property_read_u32(client->dev.of_node, "clock-frequency", > > + &initial_fout)) { > > + err = clk_set_rate(clk, initial_fout); > > + if (err) { > > + of_clk_del_provider(client->dev.of_node); > > + clk_unregister(data->hw.clk); > > Is that needed ? I would have thought it isn't because you use a devm_ function > to register it. > > Not that I understand the clk code, but getting clk from the registration > function and unregistering hw.clk (without seting it) sems a bit odd. > Is it well defined that you have to unregister hw.clk ? I have to double check. I thought the managed interface is only saving you a call to clk_put() but I may be wrong. Sören
On Fri, Sep 20, 2013 at 11:15:29AM -0700, Guenter Roeck wrote: > On Fri, Sep 20, 2013 at 10:39:17AM -0700, Soren Brinkmann wrote: [...] > > diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c > > new file mode 100644 > > index 0000000..13c2091 > > --- /dev/null > > +++ b/drivers/clk/clk-si570.c [...] > > +static int si570_probe(struct i2c_client *client, [...] > > + /* Read the requested initial output frequency from device tree */ > > + if (!of_property_read_u32(client->dev.of_node, "clock-frequency", > > + &initial_fout)) { > > + err = clk_set_rate(clk, initial_fout); > > + if (err) { > > + of_clk_del_provider(client->dev.of_node); > > + clk_unregister(data->hw.clk); > > Is that needed ? I would have thought it isn't because you use a devm_ function > to register it. > > Not that I understand the clk code, but getting clk from the registration > function and unregistering hw.clk (without seting it) sems a bit odd. > Is it well defined that you have to unregister hw.clk ? You're absolutely right. I'll remove all calls to clk_unregister(). Thanks for finding that one. Sören
diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt new file mode 100644 index 0000000..26aab5c --- /dev/null +++ b/Documentation/devicetree/bindings/clock/silabs,si570.txt @@ -0,0 +1,39 @@ +Binding for Silicon Labs 570, 571, 598 and 599 programmable +I2C clock generators. + +Reference +This binding uses the common clock binding[1]. Details about the devices can be +found in the data sheets[2][3]. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt +[2] Si570/571 Data Sheet + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf +[3] Si598/599 Data Sheet + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf + +Required properties: + - compatible: Shall be one of "silabs,si570", "silabs,si571", + "silabs,si598", "silabs,si599" + - reg: I2C device address. + - #clock-cells: From common clock bindings: Shall be 0. + - factory-fout: Factory set default frequency. This frequency is part specific. + The correct frequency for the part used has to be provided in + order to generate the correct output frequencies. For more + details, please refer to the data sheet. + - temperature-stability: Temperature stability of the device. Should be one of: + 7, 20, 50 or 100. + +Optional properties: + - clock-output-names: From common clock bindings. Recommended to be "si570". + - clock-frequency: Output frequency to generate. This defines the output + frequency set during boot. It can be reprogrammed during + runtime through the common clock framework. + +Example: + si570: clock-generator@5d { + #clock-cells = <0>; + compatible = "silabs,si570"; + temperatur-stability = <50>; + reg = <0x5d>; + factory-fout = <156250000>; + }; diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index 279407a..349b88a 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -64,6 +64,16 @@ config COMMON_CLK_SI5351 This driver supports Silicon Labs 5351A/B/C programmable clock generators. +config COMMON_CLK_SI570 + tristate "Clock driver for SiLabs 570 and compatible devices" + depends on I2C + depends on OF + select REGMAP_I2C + help + ---help--- + This driver supports Silicon Labs 570/571/598/599 programmable + clock generators. + config COMMON_CLK_S2MPS11 tristate "Clock driver for S2MPS11 MFD" depends on MFD_SEC_CORE diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 7b11106..c0e94b3 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o +obj-$(CONFIG_COMMON_CLK_SI570) += clk-si570.o obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o obj-$(CONFIG_CLK_PPC_CORENET) += clk-ppc-corenet.o diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c new file mode 100644 index 0000000..13c2091 --- /dev/null +++ b/drivers/clk/clk-si570.c @@ -0,0 +1,536 @@ +/* + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO + * + * Copyright (C) 2010, 2011 Ericsson AB. + * Copyright (C) 2011 Guenter Roeck. + * Copyright (C) 2011 - 2013 Xilinx Inc. + * + * Author: Guenter Roeck <guenter.roeck@ericsson.com> + * Sören Brinkmann <soren.brinkmann@xilinx.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk-provider.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +/* Si570 registers */ +#define SI570_REG_HS_N1 7 +#define SI570_REG_N1_RFREQ0 8 +#define SI570_REG_RFREQ1 9 +#define SI570_REG_RFREQ2 10 +#define SI570_REG_RFREQ3 11 +#define SI570_REG_RFREQ4 12 +#define SI570_REG_CONTROL 135 +#define SI570_REG_FREEZE_DCO 137 +#define SI570_DIV_OFFSET_7PPM 6 + +#define HS_DIV_SHIFT 5 +#define HS_DIV_MASK 0xe0 +#define HS_DIV_OFFSET 4 +#define N1_6_2_MASK 0x1f +#define N1_1_0_MASK 0xc0 +#define RFREQ_37_32_MASK 0x3f + +#define SI570_MIN_FREQ 10000000L +#define SI570_MAX_FREQ 1417500000L +#define SI598_MAX_FREQ 525000000L + +#define FDCO_MIN 4850000000LL +#define FDCO_MAX 5670000000LL + +#define SI570_CNTRL_RECALL (1 << 0) +#define SI570_CNTRL_FREEZE_M (1 << 5) +#define SI570_CNTRL_NEWFREQ (1 << 6) + +#define SI570_FREEZE_DCO (1 << 4) + +/** + * struct clk_si570: + * @hw: Clock hw struct + * @regmap: Device's regmap + * @div_offset: Rgister offset for dividers + * @max_freq: Maximum frequency for this device + * @fxtal: Factory xtal frequency + * @n1: Clock divider N1 + * @hs_div: Clock divider HSDIV + * @rfreq: Clock multiplier RFREQ + * @frequency: Current output frequency + * @i2c_client: I2C client pointer + */ +struct clk_si570 { + struct clk_hw hw; + struct regmap *regmap; + unsigned int div_offset; + u64 max_freq; + u64 fxtal; + unsigned int n1; + unsigned int hs_div; + u64 rfreq; + u64 frequency; + struct i2c_client *i2c_client; +}; +#define to_clk_si570(_hw) container_of(_hw, struct clk_si570, hw) + +enum clk_si570_variant { + si57x, + si59x +}; + +/** + * si570_get_divs() - Read clock dividers from HW + * @data: Pointer to struct clk_si570 + * @rfreq: Fractional multiplier (output) + * @n1: Divider N1 (output) + * @hs_div: Divider HSDIV (output) + * Returns 0 on success, negative errno otherwise. + * + * Retrieve clock dividers and multipliers from the HW. + */ +static int si570_get_divs(struct clk_si570 *data, u64 *rfreq, + unsigned int *n1, unsigned int *hs_div) +{ + int err; + u8 reg[6]; + u64 tmp; + + err = regmap_bulk_read(data->regmap, SI570_REG_HS_N1 + data->div_offset, + reg, ARRAY_SIZE(reg)); + if (err) + return err; + + *hs_div = ((reg[0] & HS_DIV_MASK) >> HS_DIV_SHIFT) + HS_DIV_OFFSET; + *n1 = ((reg[0] & N1_6_2_MASK) << 2) + ((reg[1] & N1_1_0_MASK) >> 6) + 1; + /* Handle invalid cases */ + if (*n1 > 1) + *n1 &= ~1; + + tmp = reg[1] & RFREQ_37_32_MASK; + tmp = (tmp << 8) + reg[2]; + tmp = (tmp << 8) + reg[3]; + tmp = (tmp << 8) + reg[4]; + tmp = (tmp << 8) + reg[5]; + *rfreq = tmp; + + return 0; +} + +/** + * si570_get_defaults() - Get default values + * @data: Driver data structure + * @fout: Factory frequency output + * Returns 0 on success, negative errno otherwise. + */ +static int si570_get_defaults(struct clk_si570 *data, u64 fout) +{ + int err; + u64 fdco; + + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_RECALL); + + err = si570_get_divs(data, &data->rfreq, &data->n1, &data->hs_div); + if (err) + return err; + + /* + * Accept optional precision loss to avoid arithmetic overflows. + * Acceptable per Silicon Labs Application Note AN334. + */ + fdco = fout * data->n1 * data->hs_div; + if (fdco >= (1LL << 36)) + data->fxtal = div64_u64(fdco << 24, data->rfreq >> 4); + else + data->fxtal = div64_u64(fdco << 28, data->rfreq); + + data->frequency = fout; + + return 0; +} + +/** + * si570_update_rfreq() - Update clock multiplier + * @data: Driver data structure + * Passes on regmap_bulk_write() return value. + */ +static int si570_update_rfreq(struct clk_si570 *data) +{ + u8 reg[5]; + + reg[0] = ((data->n1 - 1) << 6) | + ((data->rfreq >> 32) & RFREQ_37_32_MASK); + reg[1] = (data->rfreq >> 24) & 0xff; + reg[2] = (data->rfreq >> 16) & 0xff; + reg[3] = (data->rfreq >> 8) & 0xff; + reg[4] = data->rfreq & 0xff; + + return regmap_bulk_write(data->regmap, SI570_REG_N1_RFREQ0 + + data->div_offset, reg, ARRAY_SIZE(reg)); +} + +/** + * si570_calc_divs() - Caluclate clock dividers + * @frequency: Target frequency + * @data: Driver data structure + * @out_rfreq: RFREG fractional multiplier (output) + * @out_n1: Clock divider N1 (output) + * @out_hs_div: Clock divider HSDIV (output) + * Returns 0 on success, negative errno otherwise. + * + * Calculate the clock dividers (@out_hs_div, @out_n1) and clock multiplier + * (@out_rfreq) for a given target @frequency. + */ +static int si570_calc_divs(unsigned long frequency, struct clk_si570 *data, + u64 *out_rfreq, unsigned int *out_n1, unsigned int *out_hs_div) +{ + int i; + unsigned int n1, hs_div; + u64 fdco, best_fdco = ULLONG_MAX; + static const uint8_t si570_hs_div_values[] = { 11, 9, 7, 6, 5, 4 }; + + for (i = 0; i < ARRAY_SIZE(si570_hs_div_values); i++) { + hs_div = si570_hs_div_values[i]; + /* Calculate lowest possible value for n1 */ + n1 = div_u64(div_u64(FDCO_MIN, hs_div), frequency); + if (!n1 || (n1 & 1)) + n1++; + while (n1 <= 128) { + fdco = (u64)frequency * (u64)hs_div * (u64)n1; + if (fdco > FDCO_MAX) + break; + if (fdco >= FDCO_MIN && fdco < best_fdco) { + *out_n1 = n1; + *out_hs_div = hs_div; + *out_rfreq = div64_u64(fdco << 28, data->fxtal); + best_fdco = fdco; + } + n1 += (n1 == 1 ? 1 : 2); + } + } + + if (best_fdco == ULLONG_MAX) + return -EINVAL; + + return 0; +} + +static unsigned long si570_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + int err; + u64 rfreq, rate; + unsigned int n1, hs_div; + struct clk_si570 *data = to_clk_si570(hw); + + err = si570_get_divs(data, &rfreq, &n1, &hs_div); + if (err) { + dev_err(&data->i2c_client->dev, "unable to recalc rate\n"); + return data->frequency; + } + + rfreq = div_u64(rfreq, hs_div * n1); + rate = (data->fxtal * rfreq) >> 28; + + return rate; +} + +static long si570_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + int err; + u64 rfreq; + unsigned int n1, hs_div; + struct clk_si570 *data = to_clk_si570(hw); + + if (!rate) + return 0; + + if (div64_u64(abs(rate - data->frequency) * 10000LL, + data->frequency) < 35) { + rfreq = div64_u64((data->rfreq * rate) + + div64_u64(data->frequency, 2), data->frequency); + n1 = data->n1; + hs_div = data->hs_div; + + } else { + err = si570_calc_divs(rate, data, &rfreq, &n1, &hs_div); + if (err) { + dev_err(&data->i2c_client->dev, + "unable to round rate\n"); + return 0; + } + } + + return rate; +} + +/** + * si570_set_frequency() - Adjust output frequency + * @data: Driver data structure + * @frequency: Target frequency + * Returns 0 on success. + * + * Update output frequency for big frequency changes (> 3,500 ppm). + */ +static int si570_set_frequency(struct clk_si570 *data, unsigned long frequency) +{ + int err; + + err = si570_calc_divs(frequency, data, &data->rfreq, &data->n1, + &data->hs_div); + if (err) + return err; + + /* + * The DCO reg should be accessed with a read-modify-write operation + * per AN334 + */ + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, SI570_FREEZE_DCO); + regmap_write(data->regmap, SI570_REG_HS_N1 + data->div_offset, + ((data->hs_div - HS_DIV_OFFSET) << HS_DIV_SHIFT) | + (((data->n1 - 1) >> 2) & N1_6_2_MASK)); + si570_update_rfreq(data); + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, 0); + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_NEWFREQ); + + /* Applying a new frequency can take up to 10ms */ + usleep_range(10000, 12000); + + return 0; +} + +/** + * si570_set_frequency_small() - Adjust output frequency + * @data: Driver data structure + * @frequency: Target frequency + * Returns 0 on success. + * + * Update output frequency for small frequency changes (< 3,500 ppm). + */ +static int si570_set_frequency_small(struct clk_si570 *data, + unsigned long frequency) +{ + /* + * This is a re-implementation of DIV_ROUND_CLOSEST + * using the div64_u64 function lieu of letting the compiler + * insert EABI calls + */ + data->rfreq = div64_u64((data->rfreq * frequency) + + div_u64(data->frequency, 2), data->frequency); + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_FREEZE_M); + si570_update_rfreq(data); + regmap_write(data->regmap, SI570_REG_CONTROL, 0); + + /* Applying a new frequency (small change) can take up to 100us */ + usleep_range(100, 200); + + return 0; +} + +static int si570_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_si570 *data = to_clk_si570(hw); + struct i2c_client *client = data->i2c_client; + int err; + + if (rate < SI570_MIN_FREQ || rate > data->max_freq) { + dev_err(&client->dev, + "requested frequency %lu Hz is out of range\n", rate); + return -EINVAL; + } + + if (div64_u64(abs(rate - data->frequency) * 10000LL, + data->frequency) < 35) + err = si570_set_frequency_small(data, rate); + else + err = si570_set_frequency(data, rate); + + if (err) + return err; + + data->frequency = rate; + + return 0; +} + +static const struct clk_ops si570_clk_ops = { + .recalc_rate = si570_recalc_rate, + .round_rate = si570_round_rate, + .set_rate = si570_set_rate, +}; + +static bool si570_regmap_is_volatile(struct device *dev, unsigned int reg) +{ + switch (reg) { + case SI570_REG_CONTROL: + return true; + default: + return false; + } +} + +static bool si570_regmap_is_writeable(struct device *dev, unsigned int reg) +{ + switch (reg) { + case SI570_REG_HS_N1 ... (SI570_REG_RFREQ4 + SI570_DIV_OFFSET_7PPM): + case SI570_REG_CONTROL: + case SI570_REG_FREEZE_DCO: + return true; + default: + return false; + } +} + +static struct regmap_config si570_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .cache_type = REGCACHE_RBTREE, + .max_register = 137, + .writeable_reg = si570_regmap_is_writeable, + .volatile_reg = si570_regmap_is_volatile, +}; + +static int si570_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct clk_si570 *data; + struct clk_init_data init; + struct clk *clk; + u32 initial_fout, factory_fout, stability; + int err; + enum clk_si570_variant variant = id->driver_data; + + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + init.ops = &si570_clk_ops; + init.flags = CLK_IS_ROOT; + init.num_parents = 0; + data->hw.init = &init; + data->i2c_client = client; + + if (variant == si57x) { + err = of_property_read_u32(client->dev.of_node, + "temperature-stability", &stability); + if (err) { + dev_err(&client->dev, + "'temperature-stability' property missing\n"); + return err; + } + /* adjust register offsets for 7ppm devices */ + if (stability == 7) + data->div_offset = SI570_DIV_OFFSET_7PPM; + + data->max_freq = SI570_MAX_FREQ; + } else { + data->max_freq = SI598_MAX_FREQ; + } + + if (of_property_read_string(client->dev.of_node, "clock-output-names", + &init.name)) + init.name = client->dev.of_node->name; + + err = of_property_read_u32(client->dev.of_node, "factory-fout", + &factory_fout); + if (err) { + dev_err(&client->dev, "'factory-fout' property missing\n"); + return err; + } + + data->regmap = devm_regmap_init_i2c(client, &si570_regmap_config); + if (IS_ERR(data->regmap)) { + dev_err(&client->dev, "failed to allocate register map\n"); + return PTR_ERR(data->regmap); + } + + i2c_set_clientdata(client, data); + err = si570_get_defaults(data, factory_fout); + if (err) + return err; + + clk = devm_clk_register(&client->dev, &data->hw); + if (IS_ERR(clk)) { + dev_err(&client->dev, "clock registration failed\n"); + return PTR_ERR(clk); + } + err = of_clk_add_provider(client->dev.of_node, of_clk_src_simple_get, + clk); + if (err) { + dev_err(&client->dev, "unable to add clk provider\n"); + return err; + } + + /* Read the requested initial output frequency from device tree */ + if (!of_property_read_u32(client->dev.of_node, "clock-frequency", + &initial_fout)) { + err = clk_set_rate(clk, initial_fout); + if (err) { + of_clk_del_provider(client->dev.of_node); + clk_unregister(data->hw.clk); + return err; + } + } + + /* Display a message indicating that we've successfully registered */ + dev_info(&client->dev, "registered, current frequency %llu Hz\n", + data->frequency); + + return 0; +} + +static int si570_remove(struct i2c_client *client) +{ + struct clk_si570 *data = i2c_get_clientdata(client); + + of_clk_del_provider(client->dev.of_node); + clk_unregister(data->hw.clk); + + return 0; +} + +static const struct i2c_device_id si570_id[] = { + { "si570", si57x }, + { "si571", si57x }, + { "si598", si59x }, + { "si599", si59x }, + { } +}; +MODULE_DEVICE_TABLE(i2c, si570_id); + +static const struct of_device_id clk_si570_of_match[] = { + { .compatible = "silabs,si570" }, + { .compatible = "silabs,si571" }, + { .compatible = "silabs,si598" }, + { .compatible = "silabs,si599" }, + { }, +}; +MODULE_DEVICE_TABLE(of, clk_si570_of_match); + +static struct i2c_driver si570_driver = { + .driver = { + .name = "si570", + .of_match_table = of_match_ptr(clk_si570_of_match), + }, + .probe = si570_probe, + .remove = si570_remove, + .id_table = si570_id, +}; +module_i2c_driver(si570_driver); + +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>"); +MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xilinx.com"); +MODULE_DESCRIPTION("Si570 driver"); +MODULE_LICENSE("GPL");
Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. The devices generate low-jitter clock signals and are reprogrammable via an I2C interface. Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> --- v4: - actually check and handle error on clk_set_rate() call v3: - add delay in the path for small frequency changes, which can take up to 100us according to the data sheet - use real range for usleep_range() argument - use dev_err() over dev_warn() in set_rate() - add list of applicable devices for 7ppm DT prop - remove comments regarding platform data - ignore 7ppm DT prop for incompatible devices - replace raw numbers with #defines - convert DT prop 'temperature-stability' from boolean to u32 - make 'temperature-stability' DT prop required (actually not fully true, for 59x it is ignored and the driver does not require its presence) v2: - document clock-output-names in bindings documentation - don't use wildcards in compatibility string - change Kconfig entry to "... 570 and compatible devices" - change some indentation flaws - use 10000 as MIN and MAX value in usleep_range - fail probe() if 'factory-fout' is not provided in DT - default factory fout #defines removed - use i2c driver_data instead of OF data - remove some related structs and data - rename DT property 'initial-fout' => 'clock-frequency' (like si5351 driver) - add some more details regarding the 'factory-fout' DT property --- .../devicetree/bindings/clock/silabs,si570.txt | 39 ++ drivers/clk/Kconfig | 10 + drivers/clk/Makefile | 1 + drivers/clk/clk-si570.c | 536 +++++++++++++++++++++ 4 files changed, 586 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/silabs,si570.txt create mode 100644 drivers/clk/clk-si570.c